MS (MS) is an important cause of adult disability. Early in the disease course, damage occurs in the brain without disability. As a, many studies have found only a weak correlation between clinical disability and the volume of disease burden on brain MRI. At early stages, therefore, the brain may compensate for damage and stave off disability. These compensatory events have received little attention in MS and are the focus of the proposed pilot studies. Functional imaging studies have provided insights into multiple diseases. In some cases, functional imaging shows changes much between than findings with anatomical studies. Functional MRI (fMRI) is a method for studying brain activation with excellent temporal and spatial resolution. By performing a motor or cognitive task over a course of several minutes, brain areas activated can be identified with great anatomical precision. The proposed project will first develop fMRI paradigms over three domains (cognitive, motor and somatosensory) that are relevant to MS disability and that show low intra-subject variability across time. It will work with the Functional Neuroimaging Core (Core D) of RehabNet- West to test and refine these paradigms, as well as the quantitative interpretation of fMRI data. In the second phase of the project the refined paradigms will be used with MS subjects studied sequentially to determine the correlation of changes in fMRI activation, some of which may be indicative of functional brain plasticity, and disability.